class Solution {
public:
    char firstUniqChar(string s) {
        unordered_map<char,int>sMap;
        for(auto&e:s)
        {
            sMap[e]++;
        }
        for(auto&e:s)
        {
            if(sMap[e]==1)
            {
                return e;
            }
        }
        return ' ';
    }
};